Our aim is to create an artificial heart driven either by compressed air or electric power to totally replace the irreparable sick human heart, although human application is not covered by this Grant. We have obtained survival times in calves up to more than six months. We want to reduce the initial mortality and increase the average survival time. Manufacturing, surgical techniques and postoperative care are being perfected. Causes of failure will be defined. We will try to eliminate the occurrence of infection along the drive lines and redesign the heart to eliminate the causes of localized thrombosis, use natural valves or develop better artificial valves. The first prototype of the Jarvik electrohydraulic heart is being manufactured. Polymers used in the artificial hearts: We will improve methods of production and evaluate the blood facing surfaces before and after use. Also, define possible degeneration and loss of strength. Physiological studies using a treadmill will be undertaken to ascertain the health and normal functioning of the calves with artificial hearts. Autopsy will be performed with search for possible thromboemboli. Our purpose will be to eliminate all complications that stand in the way of human application.